according to the criterion jacket the sound was taken from a dolby surround encoded PCM 1630 digital audio master tape. It does not say it in the jacket notes but when listening to it, it certainly sounded like it was full bit rate audio. I thought it sounded even better than the dolby 5.1 and new dts mix since those were half bitrate as dvd is capable of. the sound effects and dialogue also sound more natural and less processed than the new english
dub from 2001.
Until the new anamorphic transfer on the pioneer special edition 2001 dvd was undertaken the best looking transfer was the criterion release. But the sharpness of the newer transfer certainly trumps that now.
I can confirm as someone already said the region 4 australian release from madman entertainment contains the old dub but it is sampled at half the bitrate of the criterion laserdisc and is lame dolby 2.0
both the pal and ntsc masters of the new special editions as of 2001 and on were based on a new HD telecine transfer which was downconverted to dvd. If it ever comes to HD DVD or blu ray it will be at full HD resolution as that original source as well as probalbly having both a dolby 5.1 and dts tracks at full bit rate.